The present invention relates to clamps for connecting or mating a ground wire of an electrical system to a grounding electrode, such as a water pipe or similar conduit, a grounding rod or other grounding member. More particularly it is concerned with a new and improved universal ground clamp that accommodates grounding electrodes and ground wires of various sizes or diameters.
The clamp includes a strap sub-assembly designed so as to provide full surface inter-engagement with the grounding member as well as effective edge contact therewith. The clamp also utilizes a contoured fixed platen on a single bolt to assure intimate and optimum engagement between the strap sub-assembly and the grounded conduit. Beneficially the platen facilitates a tight-fitting connection due to the contoured interrelationship between the strap and the fixed platen. At the same time it avoids any marring or gouging of the soft copper strap while imparting improved torque strength to the connection.
The new and improved clamp of the present invention provides for ease of installation and independent mounting and dismounting of the ground wire of the electrical system or the grounding electrode while at the same time providing a clamp of simple yet efficient and economical design that can be manufactured and installed in a facile manner without the need for special tools. Further the clamp provides automatic alignment between the ground wire and the grounded conduit connected thereto.
Other features and advantages of the present invention will be in part obvious and in part pointed out more in detail hereinafter.
These and related features and advantages are achieved in accordance with the present invention by providing a universal ground clamp consisting essentially of a strap sub-assembly for electrically engaging the grounding electrode and a bolt sub-assembly mounted on the strap sub-assembly and providing electrical contact with the ground wire of an electrical system. The strap sub-assembly includes an elongated flexible strap and a generally U-shaped contact bracket securely and retainably mounting one end of the strap. The bracket is beneficially provided with arcuate contact surfaces that provides excellent electrical contact with the grounding electrode. The portion of the strap adjacent the contact bracket extends tangentially of the contact surfaces to facilitate encirclement of the grounding electrode by the strap sub-assembly and promote the desired contact between the bracket and the grounding pipe.
The bolt sub-assembly of the clamp consists essentially of a single bolt having a fixed land including a rectangular platen intersecting the axis of the bolt at an intermediate position along its length. The platen has a convexly bowed elongated surface facing the lower end of the bolt, the convex surface extending in the transverse dimension of the elongated platen. A wire-receiving aperture is positioned intermediate the convexly bowed surface and the top relatively shorter end of the bolt and has an axis that extends parallel to the axis of the convex surface for receiving the ground wire of the electrical system. A clamping cap mounted on the apertured end of the bolt moves toward the platen for clampably engaging a ground wire positioned within the wire-receiving aperture. The bolt sub-assembly is mounted on the strap sub-assembly so that upon encirclement of the grounding electrode by the elongated strap the contact surfaces of the bracket engage the electrode while a portion of the strap remote from the bracket conformably engages the convexly bowed platen surface. Retaining means are provided on the bolt to draw the platen toward the bracket when securing the clamp to the electrode while additional retaining means are provided and independently operate for urging the clamping cap into clamping engagement with the ground wire positioned within the wire-receiving aperture.
A better understanding of the objects, advantages, features, properties and relationships of the invention will be obtained from the following detailed description and accompanying drawings which set forth an illustrative embodiment and are indicative of the way in which the principles of the invention are employed.